Yep, add me to the club. I almost always flare a few days before my cycle begins and feel better a couple of days into the cycle. I have never had PMS, but my MG flares follow the PMS schedule.

Once I talked my ob/gyn into supplementing my progesterone at the end of the cycle, thinking that it was the drop that was setting me off. I tried it and it made me sick, so I stopped taking it--and fell from a higher level--and ended up in the hospital for a week. So, be very careful if you decide to mess with the hormones.

Anyway, this phenomenon has been studied a bit. Two thirds of pre-menopausal women with MG experience the pre-menstural MG flare. http://www.ncbi.nlm.nih.gov/pubmed/9559997

Abby